AMD Phenom II X2 Dual Core 550 actually quad??
- Thread starter airrunner
- Start date
Unlocked and fully stable 
There's three angles on it, depending on which one you get (worst to best)
1) It's a standard dual core
2) It failed a quality test, and won't work properly if unlocked
3) It failed a quality test, but will work fine in everyday use
4) It's actually a fully functional quad core, introduced into the 550 line to make up the numbers
I've no idea if all 550s are failed quads, but some certainly are. I've also got no idea if they do indeed use fully working quads to balance the production with the demand (although there's strong suggestion that AMD have been doing this with the tri-cores)
Chances are it's failed a quality test, and since the quality tests se the bar pretty high, there's a very good chance that it will work okay if unlocked.
The best way to look at is, only buy it if you can live with a dual-core. If it turns out it works when unlocked, that's a bonus, but don't expect it or you risk dissapointment. If you need a quad, get one from the outset.
1) It's a standard dual core
2) It failed a quality test, and won't work properly if unlocked
3) It failed a quality test, but will work fine in everyday use
4) It's actually a fully functional quad core, introduced into the 550 line to make up the numbers
I've no idea if all 550s are failed quads, but some certainly are. I've also got no idea if they do indeed use fully working quads to balance the production with the demand (although there's strong suggestion that AMD have been doing this with the tri-cores)
Chances are it's failed a quality test, and since the quality tests se the bar pretty high, there's a very good chance that it will work okay if unlocked.
The best way to look at is, only buy it if you can live with a dual-core. If it turns out it works when unlocked, that's a bonus, but don't expect it or you risk dissapointment. If you need a quad, get one from the outset.
Seems to be the case that a lot are unlockable, though you do need a decent motherboard to do it, and some of the Asus boards, i believe, can unlock individual cores turning a dual into a triple if it does indeed have a single defective core.
None of them are plain dual cores. They are all manufactured using the same die as a quad core.
Some of them are indeed failed quads, but two were stable... So they just lock two. Often they fail because they don' run stable at stock voltage, but if you overclock, and increase the volts, it makes them stable. Still, they're hardware locked, so you need to use the motherboards with the correct Southbridge. You need, I think, At least an SB710 to do this. the SB750 is guaranteed to have the ACC that you need (Advanced Clock Calibration)
The reason its the southbridge that makes a difference is because there has, until now, been an unused pin on the CPU. Having this advanced southbridge means this is used to help give tasks to the southbridge instead of the CPU doing it, thus removing the need for part of the CPU to work. This allows you to bypass this hardware lock, and get them working.
Of course, if they are failed quads, you can still set up ACC, but it won't work. Worst case scenario is that it stops your PC from posting... At which point you need to reset your BIOS and start again.
Some of them are indeed failed quads, but two were stable... So they just lock two. Often they fail because they don' run stable at stock voltage, but if you overclock, and increase the volts, it makes them stable. Still, they're hardware locked, so you need to use the motherboards with the correct Southbridge. You need, I think, At least an SB710 to do this. the SB750 is guaranteed to have the ACC that you need (Advanced Clock Calibration)
The reason its the southbridge that makes a difference is because there has, until now, been an unused pin on the CPU. Having this advanced southbridge means this is used to help give tasks to the southbridge instead of the CPU doing it, thus removing the need for part of the CPU to work. This allows you to bypass this hardware lock, and get them working.
Of course, if they are failed quads, you can still set up ACC, but it won't work. Worst case scenario is that it stops your PC from posting... At which point you need to reset your BIOS and start again.
Wrong, worst case scenario is that apparently working core "dropping bits" once in a while corrupting data.
(for example what do you think HDD write does if there's error in "write address"?)
Had a P4 that did that if you overclocked it too far.. It would overwrite some of the windows boot files, next reboot you find XP is corrupted and needs a reinstall. But as you say, there is no limit to the corruption that can be achieved by a faulty or overclocked processor making bad writes to a hard disk.